CINCINNATI – The minute Reds left-handed reliever Amir Garrett starts thinking for himself on the mound is, by his admission, the time his pitching starts to “go bad.”

Just to be on the safe side, he prefers for catcher Tucker Barnhart to think for both of them.

“I put a lot of trust in Tucker on that part,” Garrett said Friday at Great American Ball Park. “Tucker’s a great teammate, man. He’s a great catcher. Me being a young guy, he does a lot for me when I’m on the mound. He knows a lot about the game. He knows a lot about the hitters. I don’t shake him off too much and when I do, he knows the next pitch I want to throw.”

Welcome to Barnhart’s world, where the job of being a Major League Baseball catcher includes equal parts talent, expertise and navigating a pitcher’s needs.

Barnhart’s talent as a ball player was underscored by his 2017 Gold Glove, a reward for defensive excellence which, in Reds annals, was previously...